These comparisons are meant to illustrate the cost effectiveness of each fuel for the consumer, and to weigh it against its environmental impact. The end result will help you decide which of the two most widely available alternative fuels (battery and LPG) is right for you.

Diesel and gas are included -- gas, because we need something to compare to, and it is the standard automotive fuel, and diesel, because it is somewhat standard for commercial use, especially when it comes to hauling heavy loads.

Energy density

These numbers vary only slightly according to different sources. With that in mind, these numbers can serve as good benchmarks. The difference between diesel, gas and propane is small. The energy density of current EV (electric vehicle batteries) is much, much smaller -- about 1/100th that of fuel. Figures are given as megaJoules per kilowatt.

• LPG: 50.2
• Gas: 46.5
• Diesel: 45.8
• Battery: 0.3

Yes, you read that right… 0.3. But there is much more to the story.

Energy efficiency

This refers to how to “accessible” the energy in a given fuel is for the current automotive technology. We felt compelled to include it so that the density of a fuel can be weighed against its efficiency. Again, sources vary slightly on these numbers. Additionally, the numbers are less concrete. They’re given in ranges, because they vary based on individual vehicles and the application, among other factors.

• Battery: 69% to 90%
• Diesel: 30% to 41%
• Gas: 16% to 30%
• LPG: No cited figures were found, but research indicates that you can expect a decrease in efficiency when converting to LPG from gas. Whether the superior energy density of LPG compensates can’t be quantified without more exact numbers.

So here, EV’s gain some ground. But at 1/100th of the density of gas, and roughly double the efficiency (according to the Department of Energy), battery power is still only about 1/50th as viable as gas. That means EV’s need a massive battery pack. The current models have a battery pack that basically covers the whole car, resting underneath the body on the chassis. This means extra weight to make up for -- and large production costs.

It's worth noting that recent improvements to gasoline engines are making gas a more efficient fuel.

Cost of refueling

This is the factor the consumer really cares about, of course.

• Battery: 26% of gas. One source cited a 74% reduction to the cost of refueling with gas. This is, of course, measured by the increase on your electric bill if you drive the same number of miles over a given period as you would with a gas car.
• LPG: 50-70% of gas. As LPG is a by product of crude oil production, the cost relationship is fairly consistent. The reduction in refueling costs varies by location and according to other factors, but you can expect it to be cheaper than gas --- enough to compensate for the reduced efficiency of LPG, and still offer substantial savings to the consumer.
• Gas: Gas is the standard fuel whose price we are so familiar with, and thus is used as the baseline.
• Diesel: the cost of diesel is typically slightly higher than that of gas.

Other cost factors to consider

First off, the costs of acquiring a vehicle are higher than gas for every other fuel. Electric vehicles are still ridiculously expensive to buy, even after substantial incentives offered by the government. Of course, the savings on refueling also subsidize the purchase. But there’s a lot of ground to make up for.

Propane-powered vehicles are the cheapest to acquire, next to gas. A gas powered vehicle is converted quite easily, which involves adding new fuel storage and a new fuel delivery system. There’s less cost to make up for than with diesel or electric.

Diesels are more expensive than gas vehicles to purchase and to maintain. The main reason diesel is a competitive fuel is because of the incredible torque advantages it offers. For loads of a certain weight, diesel is your only option (though electric semi trucks are in development). In terms of MPG, diesel is going to perform better than gas or propane. And the heavier the load, the more fuel efficient diesel becomes by comparison, because of its torque advantages.

Practicality & convenience

Before casting your lot, consider how realistic an electric vehicle or propane vehicle is for your specific situation. They both offer limited infrastructure as far as refueling goes. Long distance trips take more planning, and, frankly, are just out of the picture in some cases. An additional mark against the practicality of EV’s is the time it takes to recharge. However, if you can work it into your schedule, its not a problem.

It is a problem if you need a vehicle for all-day commercial use, though. A sitting vehicle is offering zero return-on-investment, which is why we like propane so much more for commercial use. To make propane work even better for commercial applications, you can set up a private refueling infrastructure.

This can actually be an advantage over gasoline. If your vehicles are going off route to get gas, that’s time and money spent on refueling. But if you can setup private refueling stations along your route(s), you can reduce those costs.

Environmental impact

Impact is a nuanced and charged topic. Everybody who writes about electric vehicles seems to feel that they have a dog in that fight. But there are always going to be more factors to consider, thus there is no final word. Our disclaimer is that we don’t hope to resolve the debate on what the friendliest fuel is.

The only thing we can say for certain is that cars, period, have a carbon footprint. There is one simple reason for this: the grid is powered by fossil fuels. Even when you’re charging your electric vehicle, you’re consuming fossil fuels. Sure, there are other fuels being used to power the grid. And that’s an argument for EV’s -- that it potentially uses less fossil fuels.

But the production of all vehicles requires fossil fuels, for transport of parts and materials, for power used in production, and for distribution, among other things. And the production of lithium ion batteries has its own unique set of environmental costs. (A Google search returns a wealth articles detailing this, like this one). An argument against EV’s is that the environmental cost in production per unit is actually higher. The common rebuttal to this argument is that this cost is more than paid in the decreased post-production impact. Either way, its reasonable to have some skepticism about how well quantified the impact of battery production is.

The point is, cars are not kind to the atmosphere, according to modern conventional wisdom about the environment. The goal in choosing your fuel is to minimize your impact. And LPG and battery power both offer some decreases in certain ways.

EV’s run off a grid that is powered by more than just coal, natural gas and oil. Hydro, nuclear, solar and wind all contribute. Additionally, EV’s don’t require that their “fuel” is transported all over the country to convenient locations. Where there’s electricity, there’s “fuel.”

LPG, meanwhile, is a by-product of crude production. So converting to propane reduces the demand for more wellhead locations. Propane needs to be transported still, but with your own private infrastructure, you can reduce the amount of driving done for refueling purposes. Another advantage to propane is that it burns cleaner than gas or diesel. So in the interest of reducing environmental costs, its a viable alternative.

Which is right for you?

If you can afford the upfront costs for an EV, you’ll see substantial savings on refueling. This makes them viable for private use. But with the current tech, EV’s are less practical for commercial use. The downtime needed for charging is costly, and the available models are limited, currently. LPG is a more practical alternative fuel for fleets. That’s why transport vehicles like shuttles servicing Sea-Tac Airport are using it. The cost of converting an already existing fleet is much lower than the cost of acquiring EV’s. And there are still savings. For the time being, we recommend LPG as your best alternative fuel.

You can get your maintenance and/or conversions done at ABC Auto Repair if you’re in the Des Moines area. To discuss the ins and outs of converting to, and maintaining, propane powered vehicles, you can reach us at 206-231-0995 or fill out our contact form.